In recent years, for example, as one type of travel assistance for a vehicle, travel assistance has been performed in which risk factors present around a mobile unit are determined and guidance on a result of the determination is provided. The risk factors are factors to which attention is to be paid when the mobile unit travels. Particularly, one of the risk factors is a road (hereinafter, referred to as connecting road) that connects to a traveling road of a vehicle at a divergence point present around the vehicle.
The connecting road is a road having another vehicle, a pedestrian, a bicycle, etc., moving thereon and possibly entering the traveling road of the vehicle in the future. Thus, it is very important for a driver to grasp the presence of the connecting road to pay attention beforehand to such an entry of another vehicle, a pedestrian, a bicycle, etc. For example, JP 2000-266559 A discloses that when it is determined, based on a current location of a vehicle detected by a GPS and map information, that there is a divergence point ahead on a traveling road of the vehicle, guidance on the presence of connecting roads connecting to the divergence point is provided to a driver using a display or a speaker.